html,body{
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
}
body{
    background-color: #2980b9;
}
.bubble{
    position: absolute;
    bottom: -100px;
    animation: flying infinite ease-in;
    background-color: #fff;
    border-radius: 50%;
    opacity: .5;
}
.bubble:nth-child(1){
    width: 40px;
    height: 40px;
    animation-duration: 10s;
}
.bubble:nth-child(2){
    width: 10px;
    height: 10px;
    left: 10%;
    animation-duration: 4s;
    animation-delay: 5s;
}
.bubble:nth-child(3){
    width: 30px;
    height: 30px;
    left: 20%;
    animation-duration: 10s;
    animation-delay: 3s;
}
.bubble:nth-child(4){
    width: 40px;
    height: 40px;
    left: 30%;
    animation-duration: 8s;
    animation-delay: 2s;
}
.bubble:nth-child(5){
    width: 60px;
    height: 60px;
    left: 40%;
    animation-duration: 5s;
    animation-delay: 1s;
}
.bubble:nth-child(3){
    width: 30px;
    height: 30px;
    left: 20%;
    animation-duration: 10s;
    animation-delay: 3s;
}
.bubble:nth-child(6){
    width: 20px;
    height: 20px;
    left: 50%;
    animation-duration:7s;
    animation-delay: 4s;
}
.bubble:nth-child(7){
    width: 60px;
    height: 60px;
    left: 60%;
    animation-duration: 6s;
    animation-delay: 6s;
}
.bubble:nth-child(8){
    width: 30px;
    height: 30px;
    left: 70%;
    animation-duration: 3s;
    animation-delay: 3s;
}
.bubble:nth-child(9){
    width: 80px;
    height: 80px;
    left: 80%;
    animation-duration: 8s;
    animation-delay: 1s;
}
.bubble:nth-child(10){
    width: 40px;
    height: 40px;
    left: 90%;
    animation-duration: 4s;
    animation-delay: 3s;
}


@keyframes flying{
    0%{
        bottom: -100px;
    }
    50%{
        transform: translateX(100px);
    }
    100%{
        bottom: 1000px;
        transform: translateX(-200px);
    }
}